At this point, I’ve lost track of how many times I’ve been asked, “So, you’re not even using your engineering degree?” The common assumption is that because I am not actively practicing architectural engineering, I’m not using my degree and people fail to recognize the transferable concepts and skills that carryover from engineering to training and coaching. I learned and applied fundamental principles of physics, chemistry, mechanics, thermodynamics, and energy balances all throughout my years of schooling and years in the industry. Now, I’m applying the same principles to a different medium - the human body - and using the process of engineering to optimize and adjust protocols for my clients. At its core, the engineering curriculum teaches students how to problem solve and manipulate variables to get a desired outcome or product. In the context of a building, this meant that I was designing, testing, and constructing building systems that exceeded or met the design criteria; in the context of training and coaching, this means that I am designing, testing, and constructing training programs and protocols for clients that exceed or meet their criteria, needs, and desires. The exact modalities in which I accomplish these tasks vary, but the principles and ultimate goal remains the same - get results. However, a topic I do want to dive deeper into that directly relates to my degree and associated curriculum is light. I specialized in lighting and electrical design, wherein we were taught how to calculate, manipulate, and understand how light interacts with objects in a space and influences how we interact with the space itself. I found it fascinating how manipulating different variables with the lighting (color temperature, source distribution, intensity, location, surface properties, etc.) could impact more than just our visual perception of an environment, but also our mood, behaviors, and psychological state. It’s a unique combination of quantifiable data with subjective observations - a fascinating contrast. So, I’m writing this five part series all about light (partially so that my Dad can’t say I’m not using my degree and partially because light is really cool and can be manipulated and optimized once you have a basic understanding).

So, I’ll start this series with an age-old riddle:

What color is a mirror?

It’s a very simple question that elicits a myriad of answers. Among the most common are “white,” “silver,” and “whatever color it’s reflecting,” none of which are correct. The color of the mirror is dictated by our perception of the light around us as it bounces, refracts, and interacts with the environment and reaches an equilibrium wherein our brain can process and decode the sensory inputs in order to create the “output” that we perceive as colors and shapes that form an image. The color of a mirror is a combination of the source, subject, and how our sensory receptors process and decode the information - the most important part being how our brain takes in the external sensory information and processes it to create a visual output. This visual output shapes and dictates how we view and experience the world around us. 

There are various systems within our body that are set up to and responsible for producing the visual interpretation we associate with the world around us. I’ll provide a brief breakdown to give some background before we go a bit deeper. Light enters the eye through the pupil and strikes the retina, a light sensitive tissue at the back of your eye composed of photoreceptors - rods (BW) and cones (color). It is then converted into an electrical signal that travels along the optic nerve to the chiasm, optic tracks, optic radiations, and on to the primary visual cortex (occipital lobe). It is then in the visual cortex that the electrical signal is decoded into a “blurry” picture, the association visual cortex then works to decode the rest of the information to give the picture more details (colors, depth, edges, and so forth). In addition to illuminating the subjects of our visual field, the light source and its associated output determines the type of vision that is currently being implemented in our visual pathway. There are three types of vision that are determined based on the type of photoreceptor being used in a specific lighting condition:

1. Scotopic - uses only rods to see, objects appear in black and white (very low light levels)

2. Photopic - uses only cones to see, objects appear in color (high light levels)

3. Mesopic - uses both rods and cones to see, objects appear in both black and white and color (moderate light levels)

I’m going to refer to the types of vision as our “eye sensitivity modes,” and our eyes are constantly shifting and adapting to the mode that is appropriate for the given lighting condition. High/bright lighting conditions put us in photopic vision, as the light decreases we transition into mesopic, and at very low light levels we have scotopic. Each sensitivity mode has an associated eye spectral response, wherein, there is higher sensitivity to certain wavelengths of light and lower sensitivity to others. The sensitivity curves for both scotopic and photopic vision are basic bell curves. For scotopic, the peak wavelength sensitivity is shifted slightly to the left (around 500nm - shifted towards “cooler” colors), and for photopic the peak wavelength sensitivity is shifted slightly to the right (around 550nm - shifted towards “warmer” colors). Now, we can contextualize the science and data with two common examples:

1. Have you ever noticed that things “look greener” in the dark? If you haven’t, now you will. The shift in the sensitivity curve for scotopic vision the the left means that in dark lighting conditions there’s a greater capacity to take in “green” wavelength coding information from our environment. Don’t believe me? Try looking at your houseplant in normal daylight and then close the blinds to create “dark” conditions (making sure to allow time for your eyes to fully adjust). You’ll notice that it appears more “green,” even though you did not change anything about the plant itself, only the conditions under which you were viewing it.

2. Have you ever noticed that as you walk out of a movie theater or drive out of a parking garage it slowly gets brighter as you near the exit? This is commonly referred to as a “daylight adjustment zone” and is required in design to allow your eyes time to adjust and transition from a more scotopic lighting condition to a photopic one. Lighting and electrical designers incorporate these zones to help prevent any strain associated with jumping from a very dark environment to a bright one - if you have ever come out of a dark space into direct sunlight you know the harsh strain and feeling that I’m talking about.

It’s important to understand how both scotopic and photopic vision operate on their own, however, with modern artificial lighting conditions, most of our life experiences exist utilizing mesopic vision - a combination of rods and cones to take in sensory information and produce the visual output. 

In addition to biologically describing light, we can also mathematically quantify it to get a better understanding of how sources and their associated luminous flux are illuminating a specific space. Light levels in a space are measured on workplanes, wherein a flux balance that utilizes the inverse square cosine law is used to determine the illuminance at a point at the desired height of the workplane. Illuminance measurements are important for ensuring that light levels are appropriate for a space and the tasks being performed. Furthermore, light levels and intensities work in tandem with color temperature, spectral power distributions, and other source characteristics to create various lighting conditions and scenarios that we interact with in vastly different ways.

The nuances of light expand far beyond just what we “see” and calculate. It impacts our mood, productivity, and overall impression of a space as the various inputs work together with your body to create an internal emotion and state of being. The type of light and associated wavelengths can also impact our circadian rhythm, or internal body clock, and how our body produces hormones and internal signals as we go into different phases of our day. It is important to understand both the mathematical and biological/physiological impacts and structure of light in order to optimize lighting conditions for the desired outcome. I’ve broken this blog series down into four parts in order to explore and dive deeper into the intricacies of light:

1. Quantifying Light

2. Interpreting Light

3. Psychology of Light

4. The Black Box Model

In the next four parts of this series, we will shed some light on key concepts and unleash the power of the photon as we seek to understand light and how it impacts the seven pillars of health.